F5 power amplifier

[Zen Mod]

Originally Posted by AndrewT

Juma has given you a starter value.
Ignore or follow his suggestion.
The decision is your's.

[tinitus]

I happen to agree
Not the perfect choise

But all we really need is a curcuit safe enough to power up
It just have to work without burning
THEN we can talk about perfecting it further
And we may have to realise it may still burn eventually
I wouldnt leave it out of my sight fore quite a while
I suppose its name of the game

Lets just build it, and talk later

[gaborbela]

Hello
For me it does not make sense to change the orig design JET to V fet .Even Juma first draw for the higher power rail with JET now when all design done why should I trow it out all on the window and start again something copletly different ?
Thank you any way .
I go with out cascode .
I have the layout for that to .
Thanks one more time guys , it was kind to read your advise ! I have no need more these type of help.
Greets

[udailey]

Gab,
Your board does not make a lot of sense. You have these two rails coming out from center going left and right. They have two parallel lines connected by angles that look like mountains. If this is single sided... then you have simply created a plane going to the left and a plane to the right. So are the mountains just for looks or what is the point? Do you have any kind of silkscreen so we can see what you are trying to do? The schematic along with that board is not going to help a lot except that we can guess easily which are mosfets and which are resistors going to mosfets. Other than that its a bit confusing. Just to be clear I have no intention of diagnosing your FX-5 circuit as it is beyond me, but I am pretty sure that board is either designed for looks, making it confusing, or designed wrong.
Uriah

[tinitus]

I have never seen nothing but good behaviour in the PASS forum
Im sure its obvious why
Or maybe it isnt
Maybe it wont last forever
But please, lets try not to spoil it

[Renron]

Udailey,
Positive, HELPFUL, well thought out, informative, direct and concise.

Well Done, great post!

Ron

[bobodioulasso]

The fun of that story is that the regular F5 is a very good sounding proven design 100% warranted very simple to build without any headache.
Aren't you simply curious to listen to it?
Or are you smarter than Papa?
Not to forget that a distortion analyser should be helpfull to tweak the mods.

[udailey]

Originally Posted by tinitus

I have never seen nothing but good behaviour in the PASS forum
Im sure its obvious why
Or maybe it isnt
Maybe it wont last forever
But please, lets try not to spoil it

Tinitus,
There was no maliciousness in my post whatsoever. None.
Uriah

[brianco]

What does concern me is that this whole matter regarding an up-rated F5 should have been split from the main F5 thread very early on.

To attempt to find anything regarding the F5 - as originally gifted by Nelson Pass - is like looking for a needle in a haystack....a haystack of almost 6000 postings!

[gaborbela]

Hello
The board was design by hand , there is no silkscreen unfortunately .
Sorry about that . The reason I wrote I want to stick the orig design !It take me hours to draw a layout like these by hand .
These is not a SECRET or something I just don't have any silkscreen .
You can find the schematic in the last couple page if you seriously interested .
For me it make sense , I DESIGN many working boards like these with out any software . And always work out fine .
I posted the cascoded the input before .But I will posted one more time and also the full schematic .
My orig question was : The cascode was design to 40V rail , now I go with lower voltage actually 24V rail .So if I want the cascode to work fine do I have to use lower value resistor to connect the cascode to the rail and to the ground or to the JET source.

Greets